Disruptive behavior disorders, particularly Attention-Deficit/Hyperactivity Disorder (ADHD), constitute one of the most common diagnoses in preschool children (1). Disruptive behaviors are a major public health problem including causing significant emotional distress for caregivers and children, expulsion from daycare or early education settings, demands on caregiver's time, accident proneness and other safety concerns (2, 3). However, few evidence-based early interventions exist for preschoolers with attention and behavior problems, which is critical because they are strongly suggested as the first line of treatment for preschoolers with ADHD (4). Because executive functioning (EF) has been consistently been proposed as a putative factor in the development of disruptive behavior disorders an intervention targeting EF (e.g., inhibition, working memory), attention, and metacognition during early childhood could likely affect the development of disruptive behavior disorders in preschoolers. Indeed, EF skills are identified by kindergarten teachers as primary prerequisites for school success (5). EF deficits independently contribute to poorer outcomes in ADHD (6-8), and have been linked directly to academic (9-11) and social functioning deficits (12-14). Given that EF and brain development are rapidly developing during the preschool years (15), preschoolers may benefit most from an early intervention targeting EF skills. We have developed a promising intervention, Executive Training of Attention and Metacognition (ETAM), for preschoolers, and have conducted a small preliminary open trial demonstrating the initial acceptability of the intervention. We also found significant moderate effect sizes on objective measures of EF (16) and moderate to large effect size reductions in ratings of inattention and behavioral symptoms by parents, clinicians, and teachers. An RCT is needed to investigate if these positive effects on executive functioning, attention, and behavior are due to ETAM or to the effect of parental attention and/or a placebo effect. Consistent with the parameters of the R34 mechanism we propose to assess the feasibility of a design for a future RCT. We will develop an attention control (AC) comparison group and assess the feasibility of: identifying, enrolling and retaining preschoolers at-risk for ADHD, randomization choices, the measurement of EF and functional outcomes, and delivery protocol for both AC and ETAM by conducting a pilot RCT with 60 children at-risk for ADHD. Exploratory aims include assessing whether children in the ETAM group show gains compared to those in AC on targeted (trained) outcomes (i.e., measures of EF) and untrained outcomes (i.e., ADHD symptoms, academic readiness, social competence). We will also assess whether gains are maintained as well as investigate potential moderators/mediators. Given the relation of EF to a number of aspects of child development-including academic skills, social competence, and risk for psychopathology-research promoting EF in young children is a scientific priority.